Circuits achieving an electric model being equivalent to a negative capacitor are already known in the art, as shown in the following publications.
The document “Using a negative capacitance to increase the tuning range of a varactor diode in MMIC technology”, Svilen Kolev, IEEE Transactions on microwave theory and techniques, December 2001, discloses a first application of such a negative capacitance circuit.
Another application of such a circuit is disclosed in this publication “Generation of negative capacitance in a common gate MESFET stage and application to optical receiver design at microwave frequencies”, Jason D Drew, Wideband circuits, modeling and techniques, IEE colloquium, May 1996.
However, one may notice that such circuits can not be used for high frequencies applications, operating at frequencies beyond 2 Ghz in BiCMOS technology.